Electrical plug connectors are intended to produce a releasable electrical connection via their plug connector pairs, therefore via their socket parts and plug parts, for example between an electrical line and a further electrical line or an electrical apparatus.
Here, different connection methods are known in the prior art for connecting a cable or an electrical line to the plug connector.
Besides screw connections, crimp connections, soldered connections, press-in or piercing connections and other connection techniques are known, such as form-fit connections, in particular welded connections.
In most applications it is usually desirable to produce a particularly durable connection between the contact of an electrical plug connector and the cable to be connected.
In particular in the automotive industry, high demands are placed on the durability and reliability of an electrical connection.
In particular it is a requirement that, in a reliable and lasting manner, the line to be connected to the contact does not lead to a detachment of the connection, even when exposed to temperature fluctuations and mechanical vibrations and interferences during use of the vehicle.
The current and future developments of electric motors and hybrid technology in the automotive sector also require contact arrangements with high current-carrying capability that produce a reliable connection even at increased temperatures, in particular as a result of inherent heating.
With temperature-change operation, such contact materials in particular are not suitable, since they fail over time as a result of relaxation processes with the alternating temperature rise and cooling and may detach from the cable.
The ultrasonic welding process has proven to be a particularly suitable welding process for producing high-strength connections of certain materials, but again encounters significant problems with the connection of certain contact materials.
There are thus various tests for ascertaining which material damage occurs when sufficient welding energy is applied by ultrasonic welding.
In material tests it has been found that the connection portions of contact pins suffer considerable damage in part and have a tendency to crack formation when a copper cable is connected to a copper contact by means of ultrasonic welding.
In addition, there are fundamental questions concerning the correct design of contact geometries for the reliable design of an ultrasonic weld to a cable.